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---
name: codex-loop
description: Fix Elixir/Phoenix code until Codex CLI review comes back clean — bounded review, fix, verify loop before opening a PR. Use when codex is installed and you want an external cross-model critic on your changes before pushing.
effort: medium
argument-hint: "[--base <branch>] [--uncommitted] [--auto] [--max-rounds N]"
---
# Codex Loop (fix until clean)
Critic→Refiner loop with the Codex CLI as external critic: review → fix
approved findings → verify → re-review, until codex is clean or rounds run
out. Codex reviews; Claude fixes. Complements `/phx:review` (Claude panel)
— run either or both before a PR.
## Usage
```
/phx:codex-loop # diff vs default branch, interactive
/phx:codex-loop --uncommitted # staged + unstaged + untracked
/phx:codex-loop --base develop # explicit base branch
/phx:codex-loop --auto # auto-approve P0/P1/P2, skip P3
/phx:codex-loop --max-rounds 2 # default 3
```
## Iron Laws
1. **BOUNDED rounds — never exceed --max-rounds (default 3)** — each round
costs codex quota; report remaining findings instead of looping on
2. **Verify BEFORE re-review** — `mix compile --warnings-as-errors` + tests
must pass before burning a codex round on broken code
3. **NEVER commit or push** — leave git to the user
4. **Codex findings get Iron Law scrutiny** — decline suggestions that
violate an Iron Law, with explanation in the round report
5. **Skipped findings are reported, never dropped** — every finding ends as
fixed, declined (with reason), or deferred-by-user
6. **Missing CLI stops the skill with an install hint** — suggest
`/phx:review` as the codex-free alternative; never crash
## Workflow
### Step 1: Preflight
Run `command -v codex`. If missing: STOP.
Show the install hint (`brew install codex` or `npm i -g @openai/codex`,
then `codex login`; `codex doctor` to diagnose) and suggest `/phx:review`.
Then two cheap checks that save review rounds:
- **Dirty tree** (`git status --short`, only when using `--base`): codex
inspects working-tree state too and WILL flag local dirt (stray edits,
dirty submodules) as findings. Surface the dirt and ask: clean/stash
first, or proceed knowing round 1 may spend findings on it.
- **Missing rubric**: if `AGENTS.md` has no `## Review guidelines`
section, note once that `/phx:init` installs the Elixir rubric that
steers codex priorities — then proceed (it works without, on defaults).
### Step 2: Detect Diff Mode
- **Flag passed** (`--base`/`--uncommitted`) → use as given
- **Commits ahead of the default branch** → `--base {default}`
- **No commits yet** → `--uncommitted`
### Step 3: Round Loop (max `--max-rounds`, default 3)
1. **Review** — ONE foreground Bash call, explicit `timeout: 600000`
(large diffs run 10+ min). On timeout with the process alive: ONE
`until [ -f {out} ]; do sleep 5; done` wait — never poll-spam or
`pkill` a running review (quota is spent either way). ALWAYS silence
the streams — only the `-o` file matters (10k+ lines otherwise):
```bash
codex exec review --base {branch} --ephemeral \
-o /tmp/codex-round-{n}.md > /tmp/codex-round-{n}.log 2>&1
```
NEVER pass custom instructions with a diff-mode flag — the CLI rejects
the combination; the rubric comes from AGENTS.md `## Review guidelines`
(`/phx:init`). Parse the output file, NOT the exit code (0 even with
findings). Recipes: `${CLAUDE_SKILL_DIR}/references/codex-cli.md`.
2. **Clean check** — parse the output file; no `- [P{n}]` bullets means
CLEAN → go to Step 4.
3. **Triage** — emit the findings table
(`# | P | file:line | title | proposed action`) as **visible
response text BEFORE any `AskUserQuestion` call** — a table composed
only in thinking never renders. Then ask approve-or-skip per finding
(`AskUserQuestion`). With `--auto`: approve P0/P1/P2, skip P3 (list
skipped in the round report).
4. **Fix** — apply approved fixes with user-visible diffs. Check each
against Iron Laws first (Law 4).
5. **Verify** — scoped, before the next round:
```bash
mix format {changed_files} && \
mix compile --warnings-as-errors && mix test {affected_tests}
```
If verification fails 3 times, STOP with a BLOCKER report — do not
burn another codex round on broken code.
6. Next round (n+1).
### Step 4: Final Report
```markdown
## Codex Loop Report — {CLEAN | MAX ROUNDS REACHED | BLOCKED}
Rounds: {n}/{max} | Fixed: {n} | Declined (Iron Law): {n} | Deferred: {n}
{per-round: findings → outcome}
{remaining findings if not CLEAN}
```
On CLEAN: suggest `/phx:compound` for non-obvious fixes, then commit/PR.
On MAX ROUNDS: list remaining findings; offer `/phx:plan` to convert them
into a follow-up plan.
## Integration
```text
implement → /phx:codex-loop (YOU ARE HERE) → clean → commit/PR → /phx:watch-pr --codex
↑ or arrive from /phx:review --codex verdict REQUIRES CHANGES
```
## References
- `${CLAUDE_SKILL_DIR}/references/codex-cli.md` — invocation recipes, parse
patterns, verified gotchas (CLI 0.142.5)